Video Transcript
Which row, A, B, C, or D, in the following table correctly compares the main
functions of the four major types of animal tissue?
In the table, each row gives a comparison of the functions of the four types of
animal tissues. However, only one of the rows contains the correct comparison. Let’s briefly review each of the tissue types so we can identify it.
Epithelial tissue covers most of our internal and external body surfaces. It can be found in the outer layer of the skin, called the epidermis, and the lining
of blood vessels, represented in blue in the diagram. It serves to protect our bodies and organs, as well as to secrete important
substances and absorb others. For example, the epithelial cells in our eyes secrete mucus to protect and lubricate
them.
Connective tissue is found between other types of tissue everywhere in the body. It comes in a wide diversity of forms, from tendons and ligaments to bones and
blood. Its main functions are to connect, attach, support, and bind to different structures
in the body.
Muscular tissue contracts and relaxes to produce movement of the body. There are three kinds of muscular tissue. Skeletal muscle is in charge of voluntary movements. Smooth muscle produces involuntary movement of our internal organs and ducts. Finally, cardiac muscle is found in the heart. It involuntarily contracts rhythmically and continuously in order to pump blood
throughout the body.
Nervous tissue is responsible for communication in the body. Nerves, represented in green in the diagram, send messages to the spinal cord. The spinal cord delivers these messages to the brain. The brain then processes the information and sends messages about how to respond back
to the spinal cord and nerves.
Now that we know the main functions of each of these tissue types, we can see that
row (A) of our table contains the correct comparison.
